A. Field of the Invention
The Invention relates to the field of roof ventilation and particularly to ventilation of a roof through the upper side of the roof deck. The Invention is an above-the-deck ventilated roof featuring an end cap.
B. Description of the Related Art
The portion of a building roof that is exposed to the elements is protected by a durable, weather-resistant surface, such as shingles. As used in this document, the term ‘shingle’ means tab shingles, architectural shingles, cementatious shingles, metal shingles, slate, sheet metal, tar paper, roll roofing, ceramic tile roofing, wood shakes, synthetic versions of any of the above and any other weather proofing product that may be applied to a pitched roof.
The shingles are supported by a roof deck. As used in this document, a ‘roof deck’ means the generally planar structural covering the upper side of a building and providing support for shingles. The ‘roof deck’ usually is composed of wood in the form of plywood sheets or dimensioned lumber. The term ‘roof deck’ also may include other roofing materials previously applied to the plywood or dimensioned lumber, such as tar paper, ice and water shields, and shingles.
The roof deck has a pitch from the lower edge of the roof to the peak of the roof so that water and snow will fall from the roof. When shingles are applied to a roof deck, the shingles proximal to the lower edge of the roof are applied first and attached to the deck. Each subsequent course of shingles proceeding from the lower edge to the peak of the roof overlaps the preceding course so that water running from each shingle flows onto the top of the adjacent downhill shingle. The shingles cooperate to form a composite surface that is tight to rain water and snow melt.
Ventilation of the space under the roof is important to reduce condensation and the resulting moisture damage to the roof and to the building structure. Ventilation also serves to allow air heated by solar gain to escape from the space under the roof, reducing the cooling load on the building.
To ventilate a roof, air must both enter and leave the space under the roof. Because air under the roof is heated by solar gain and because heated air rises, the exit for air from a space under a roof usually is a vent located in a wall or a ridge vent located at the peak of the roof. Air entering the space under the roof may enter through vents installed in a soffit; that is, the underside of the portion of a roof overhanging the exterior walls of the building. Historically, the roofs of many buildings effectively were not ventilated because the buildings lacked soffits and had little or no way for air to enter the space under the roof.
An apparatus to allow air to ventilate the space under a building roof is addressed by U.S. Pat. Nos. 6,212,833 and 6,447,392 issued Apr. 10, 2001 and Sep. 10, 2002, respectively, to the inventor of the present Invention. The '833 and '392 patents address above-the-deck roof ventilation. The teachings of U.S. Pat. Nos. 6,212,833 and 6,447,392 are incorporated by reference as if set forth in full herein.
In the roof ventilation apparatus and system taught by the '392 and '833 patents, the air inlet or exhaust for a roof is an elongated vent located on the upper side of the roof deck. The elongated vent includes a vent shingle support. The vent shingle support has a width and a length that is large compared to its thickness. The vent shingle support has a downhill side and an uphill side. The downhill side of the vent shingle support is supported in a spaced-apart relation with the roof deck, the space between the roof deck and the vent shingle support at the downhill side defines the air intake. The air intake communicates through the interior volume of the elongated vent to a slot defined by the roof deck. The slot communicates with the space under the roof.
In use, air enters the air intake defined by the space between the downhill side of the vent shingle support and the roof deck. The air passes between the elongated vent shingle support and the roof deck, and passing through the slot defined by the roof deck into the space under the roof.
The uphill side of the vent shingle support is not spaced apart from the roof deck. When shingles are applied to the roof, the shingles are applied to the elongated vent shingle support and to the roof deck to the uphill side of the elongated vent shingle support so that the shingles overlap both the vent shingle support and the roof deck uphill from the vent shingle support. The shingles covering the elongated vent and the roof deck form the continuous, rain and snow melt-tight surface.
A potential issue with respect to the prior art above-the-deck roof vents occurs at either end of the elongated vent if the elongated vent is not properly installed. If the elongated vent is terminated at a location other than the gable edge of the roof deck, the shingles overlapping the end of the elongated vent are supported by the vent shingle support, but are not supported by the deck adjacent to the vent shingle support due to the spaced-apart relation between the vent shingle support and the roof deck at the downhill side of the elongated vent. The lack of support by the roof deck at the end of the incorrectly-installed elongated vent can result in failure of the shingles adjacent to the end of the elongated vent.
The prior art above-the-deck roof vent may be terminated at a valley formed by the intersection of two roof decks. Proper installation of the prior art elongated vent in this circumstance is to trim the end of the vent to conform to the valley, which fully supports shingles overlapping the end of the elongated vent. If the elongated vent is not trimmed in this circumstance, the shingles overlapping the end of the elongated vent are not supported and may fail.
The potential failure of an improperly installed roof vent adjacent to the end of the vent is a characteristic of all current above-the-deck roof ventilation systems.